There is no single test to diagnose ADHD. Therefore, a comprehensive evaluation is necessary to establish a diagnosis, rule out other causes, and determine the presence or absence of co-existing conditions. Such an evaluation requires time and effort and should include a careful history and a clinical assessment of the individual’s academic, social, and emotional functioning and developmental level.
There are several types of professionals who can diagnose ADHD, including clinical psychologists, clinical social workers, nurse practitioners, neurologists, psychiatrists and pediatricians. Regardless of who does the evaluation, the use of the DSM-5 diagnostic criteria for ADHD is necessary.
Determining if a child has ADHD is a complex process. Many biological and psychological problems can contribute to symptoms similar to those exhibited by children with ADHD. For example, anxiety, depression and certain types of learning disabilities may cause similar symptoms. In some cases, these other conditions may actually be the primary diagnosis; in others, these conditions may co-exist with ADHD. A thorough history should be taken from the parents and teachers, and when appropriate, from the child. Checklists for rating ADHD symptoms and ruling out other disabilities are often used by clinicians; these instruments factor in age-appropriate behaviors and show when symptoms are extreme for the child’s developmental level.
For adults, diagnosis also involves gathering information from multiple sources, which can include ADHD symptom checklists, standardized behavior rating scales, a detailed history of past and current functioning, and information obtained from family members or significant others who know the person well. ADHD cannot be diagnosed accurately just from brief office observations or just by talking to the person. The person may not always exhibit the symptoms of ADHD in the office, and the diagnostician needs to take a thorough history of the individual’s life. A diagnosis of ADHD must include consideration of the possible presence of co-occurring conditions.
As part of the evaluation, a physician should conduct a thorough examination, including assessment of hearing and vision to rule out other medical problems that may be causing symptoms similar to ADHD. In rare cases, persons with ADHD may also have a thyroid dysfunction. Diagnosing ADHD in an adult requires an evaluation of the history of childhood problems in behavior and academic domains, as well as examination of current symptoms and coping strategies.